Posted by barb on Jun 30, 2004 in
Science Musings A couple quick notes on news from the world of astronomy:
- The Cassini spacecraft is poised to take orbit around Saturn. They will be firing it’s engines starting at about 10:30 PM (Eastern Daylight Time) tonight to put the spacecraft in orbit. Anyone in the DC/Baltimore metro area is invited to the Goddard Space Flight Center’s Visitor Center this evening to watch the JPL mission operations center, hear GSFC people involved in Cassini speak, and participate in some sky-viewing with the GSFC astronomy club. The activities start at 7PM.
- Astronomers have reported finding a very old, very massive black hole: Massive Black Hole Stumps Researchers. The blazar hosting this black hole is at a distance of about 12.7 billion light years, which puts it’s formation at just about a billion years after the Universe formed. Astronomers aren’t sure, yet, how supermassive black holes form, but this one became very large, very quickly, so may put some limits on formation theories. (The original paper appears in The Astrophyisical Journal Letters, volume 610. Subscription is required to view article on-line.)
Posted by barb on Jun 25, 2004 in
Science Musings Somehow I know just how to find them. I was Googling for “GZK cutoff”, since I had just read an article disputing the existence of the GZK cutoff*, and I wanted a bit more information. (Plus, the authors of the paper did not indicate whether or not they had submitted the paper anywhere, and I was wondering if they were giving accurate information.)
The first link I went to was an article on UHECR [link disappeared from the Web] (ultra high-energy cosmic rays). I grew suspicious of the author when I read the following:
They say that energy losses suffered by ultra high energy cosmic rays by meson-producing interactions with photons of the big-bang relic background radiation would have a profound effect on what we can “see.”
Why was I suspicious? Most scientists would not say “big-bang relic background radiation”, but would simply say CMB or perhaps cosmic microwave background. I thought I should investigate the author a bit more.
I checked out his resume [link disappeared from the Web] and found that he has a bachelor’s degree in electrical engineering, and most of his experience is in computer programming. Now, I’m not saying that amateur astronomers can’t contribute to astronomy research, they absolutely can. He is not one of them.
What really gets me is that he was presented posters at American Astronomical Society Meetings. His abstract for his poster at the January 2004 Meeting was fairly vague; however, I’m not sure how his poster for the October 2002 Planetary Division Meeting was accepted.
And frankly, anyone referencing Velikovsky in the first paragraph of an article [link disappeared from the Web] should not be taken seriously.
I just can’t leave this guy’s site…it’s so bad. He talks about gamma-rays “tickling-to-death” heavy elements in the solar wind, and energies of gamma-rays in terms of Hertz (X-ray and gamma-ray astronomers always use keV or MeV to describe the spectrum). Few of the references in his article are to referred science journals, and those that are do not reference his theories at all.
I just need to turn it off…this is not good for me.
* The spectrum of cosmic rays (relativistic particles, usually protons) that have been detected at Earth is theorized to have a “cut-off” at energies above 1020 eV, because such particles will be absorbed by the cosmic microwave background. (For more, check out the GZK Limit article at Wikipedia.)
Posted by barb on Jun 24, 2004 in
Science Musings A couple random things I came across while searching for news items mentioning Constellation-X:
- The telescope will be 400 years old in 2008! Here’s a cool article at Space Today about the history and future of the telescope:
The 400th Anniversary of the Telescope[link removed 9/2015 – no longer exists]
- This web site, UFO Area, quoted a press release on Chandra’s latest contribution to dark energy research. I had already come across the release, but when I saw the domain name, I thought I’d poke around. This is one of those fun, ridiculous sites collecting evidence of UFOs, ancient mysteries, and conspiracies.
Posted by barb on Jun 17, 2004 in
Science Musings There’s been a lot in the news about various astronomy events, so I thought I’d summarize a few of them here:
- Space.com has an exclusive article answering the questions of where Kerry stands on the whole Bush moon-and-Mars plan, Kerry Criticizes Bush for Space Vision.
“NASA is an invaluable asset to the American people and must receive adequate resources to continue its important mission of exploration,” Kerry wrote. “However, there is little to be gained from a ‘Bush space initiative’ that throws out lofty goals, but fails to support those goals with realistic funding.”
This is all quite true — there is little chance that the initiative will succeed given the modest funding Bush has proposed. Kerry does also mention the cancelled servicing of Hubble; however, I was disappointed that there was nothing in the article about other space science missions. The rerouting of funds to the human space flight projects has really curtailed some of the upcoming (next decade or so) space science missions.
- Another Space.com article, Odd Black Hole Defies Explanation, describes results of a study by Harvard-Smithsonian Center for Astrophysics scientists that has found the best evidence for an intermediate black hole yet.
There have traditionally been two types of black holes observed: “galactic” black holes with masses on the order of a few times that of our sun and “supermassive” black holes with masses millions of times that of our sun (and found in the centers of galaxies). One outstanding question has been how do supermassive black holes form, and if they start as smaller black holes and form by “eating” materials that fall within it’s gravitational influence, then where are the intermediate black holes — the ones with masses between the galactic and supermassive black holes.
Yet several attempts to identify middleweights, those suspected of weighing hundreds or thousands of times as much as the Sun, have not fully panned out. Some astronomers think middleweights might have been very important in the early universe, serving is an intermediate stage in the development of a stellar black hole into one of supermassive proportions. If so, there ought to be a few that didn’t fully evolve and are still around as middleweights.
Naturally, it’s always exciting when evidence for a new, previously un-observed object comes along. This particular type of object may provide clues to the origins of the supermassive black holes. (These results were presented at the 204th meeting of the American Astronomical Society, 30 May – 3 June 2004 in Denver, Colorado.)
- Astronomers have also seen evidence of a black hole (or possibly neutron star) in the midst of the remnant of a very recent supernova: Youngest Possible Black Hole Spotted Near Birth
It is the closest researchers have come to witnessing the birth of a black hole, from the explosion two decades ago to the recent emergence of a dense object amid the chaotic scene. The object may be a neutron star instead of a black hole, however. Scientists hope to figure that out with continuing observations, they said Thursday.
Evidence of black holes and neutron stars has been seen previously in supernova remnants; however, the remnants are centuries old. This is the first time astronomers have observed a supernova, and then less the 20 years later observed a compact object within the supernova remnant. While the connection between supernovae and black holes/neutron stars has been well accepted by astronomers, this is an exciting observation to strengthen that connection. (The full article is in the 11 June 2004 issue of Science.)
Posted by barb on May 28, 2004 in
Science Musings About one week out of every six I answer half of the questions that come into the Ask a High Energy Astronomer web service. I usually end up doing web searches for some of the answers, or to clarify my own understanding to put the answer into words a non-specialist will get. During those web searches, I often come across the weirdest crap on the web.
Today I was just searching for the radial velocity of Alpha Centauri, and came across a page by a guy who has written a thesis (215 pages, he claims), called Logical Physics, on the nature of light. He decided that the physicists have it wrong, based on his studies of light refracted by a 90° prism. Among his conclusions are the re-introduction of the ether, angular momentum doesn’t have any bearing on the position of planets in the solar system, the sun was created from the ether, the moon has nearly 3 times the mass currently accepted by astronomers….the list goes on. Fortunately, the web page informs us that the book is completely sold out. Though, it might be fun to read when I’m depressed — it’s sure to be a laugh-fest.
Posted by barb on May 21, 2004 in
Science Musings I found this transcript of O’Keefe’s tesitmony before the House Appropriations Committee last month (April 21) while looking for press releases.
Frankly, I found the chairman’s comments before O’Keefe’s testimony more interesting that the testimony itself. He gives a summary of what the proposed budget cuts will to do various NASA projects.
For example, let’s look at the initial fiscal year ’04 operating plan, in which significant changes open the door to more radical changes and follow-on to fiscal year ’04 operating plans.
In the space science enterprise, they include cuts to Project Prometheus, cuts to Space Science Technologies and Advanced Concepts, Constellation X and re-submissions, cuts to the Living With a Star, totally about $150 million.
There are even more specific cuts, delays and cancellations in the fiscal year ’05 budget proposal. For example, in the Space Science Enterprise, Hubble’s fourth servicing mission is canceled. The Jupiter Icy Moon’s orbiter mission is delayed by three years. Explorer Constellation X and re-submissions are delayed. In the Earth science enterprise, global precipitation missions and the Earth systems path-finders are deferred. Research and technology funding is frozen.
In the biological and physical science enterprise, research in International Space Station is cut by $1.2 billion from fiscal year ’05 to fiscal year ’09.
In cross-cutting technologies, next-generation launch technologies are terminated.
I have the feeling that much of the public thinks that all of NASA stands firmly behind the moon/Mars plan. The truth is that the new vision is a boon for a few select divisions at NASA, but that many science programs are going to suffer. Programs that have been under developement for years and that were promised ful funding in FY04. Those programs are now fighting to stay afloat. The plan cuts into much of the “real science” that NASA has been nurturing in favor of a flashy new vision.
I’m not saying that NASA shouldn’t have a unified vision. I’m also not saying that a plan to send humans back to the moon and beyond is not an exciting vision. The problem is the speed and voracity with which the administration is trying to implement the plan.
The chairman also quoted from Bush’s January 14th speech:
The president in his January 14th announcement of this proposal stated, and I quote, The vision I outline today is a journey, not a race, end of quote.
It seems that the speed with which NASA seeks to implement this proposal certainly makes us feel like we’re in a race.
I absolutely agree that NASA needs a unifying vision for the future, and I see that the public has had a hard time grasping the work that NASA has done over the past several years. However, the administration changes and budget cuts (for select programs) have been so swift and unexpected that it smacks of a desparation on the part of the executive branch to leave its mark on NASA and NASA’s future.
Sending men and women to Mars is exciting, but it needs more than a few committee meetings and the presidential stamp of approval before it overturns strong science efforts. Nor does it need to muscle it’s way past missions that promise to unlock some of the long-standing mysteries of the Universe.
Posted by barb on May 13, 2004 in
Science Musings As part of my work, I’ve helped out on several conference proceedings and science papers. The latest one now appears in the astro-ph archive. The paper will appear in The Astrophysical Journal in August.
The paper describes an upcoming NASA mission (along with collaborators from other organizations and countries) designed to study gamma-ray bursts (GRBs).
GRBs were discovered in the 1960s when the Vela satellites observed bright flashes of gamma-rays. The Vela satellites were designed to watch for violations of the Nuclear Test Ban Treaty, and were watching the Earth for gamma-rays, since nuclear explosions emit strongly in gamma-rays. Instead, they observed cosmic flashes of gamma-rays (known to come from outside the Earth by triangulation of signals recieved from the different satellites).
Since then, GRBs have been largely a mystery. In 1997, BeppoSAX, an Italian X-ray astronomy mission, discovered X-ray afterglow from a GRB. From the afterglow observations, we now know that at least one class of GRBs is cosmological in distance (i.e. they do not come from our solar system or even our galaxy — they originate at distances halfway across the known Universe).
Afterglow has now been observed in X-ray, optical, and radio wavelengths (and everything in between). The key to understanding what causes GRBs is in using multiwavelength observations to map the evolution of radiation from a GRB.
That’s where the Swift mission comes into the picture. It is a satellite that will carry a gamma-ray all-sky telescope that will watch for a GRB to take place. As soon as it detects a GRB, the satellite will autonomously slew to bring the burst into the fields-of-view of its X-ray and optical telescopes. Within about a minute, the burst will be observed by three different wavebands simulateously.
In the past year, GRBs have been tied to supernovae in distant galaxies, but there are still several mysteries to solve about GRBs. For example, there is another class of GRBs whose origin has not been explained, though may be related to two orbitting neutron stars that collide. Also, since GRBs lie at cosmological distances, they might be useful for studying the Universe at high redshift, when it was much, much younger than it is now.
Posted by barb on Apr 20, 2004 in
Science Musings The Gravity Probe B satellite has launched!
According to Einstein’s theory of relativity, any spinning massive body (like the Earth, the Sun, a black hole) will not only distort space, but will drag space along with it as it spins. This frame-dragging is a fairly small effect for a body like the Earth, but with the instruments aboard the Gravity Probe B, it should be measureable.
You might wonder why we need another test of Einstein’s theory. He’s a household name, afterall, and his theories have stood up against many other tests.
It’s true that Einstein’s theory has worked extremely well to explain, for example, the bending of starlight measured during solar eclipses and Mercury’s peculiar orbit and rotation. However, no matter how well a theory stands up, it is still open to further testing. That’s what science is all about.
Up to this point, frame dragging has not been directly measured, even though the effect has been known for over 50 years. The problem is that the best place to test frame dragging would be around a black hole, but we don’t have one handy. So we had to wait until we could develop sensitive enough instruments to test it on the Earth.
The results should prove interesting, but we’ll have to wait about a year for those.
Posted by barb on Jan 28, 2004 in
Science Musings I saw this article on Salon today:
Senators skeptical about Bush’s NASA vision
Skeptical senators grilled NASA administrator Sean O’Keefe on Wednesday on whether President Bush’s vision of returning astronauts to the Moon and exploring Mars is feasible in light of strained federal budgets. … To pay for the project, Bush plans to request a 5-year, $1 billion increase in NASA’s budget with an additional $11 billion diverted from other NASA projects.
Since I work at NASA, it might be bad for my career, politically, to say much about the Bush moon-plan. Let me just point out two things: 1) I do not work for the human space flight division; and 2) Note that in the text I included above that part of the plan is to take $11 billion from other NASA projects.
‘Nuff said.
Posted by barb on Dec 12, 2003 in
Science Musings Influence of Solar Activity on State of Wheat Market in Medieval England
From the abstract:
The database of Prof. Rogers (1887), which includes wheat prices in England in the Middle Ages, was used to search for a possible influence of solar activity on the wheat market. We present a conceptual model of possible modes for sensitivity of wheat prices to weather conditions, caused by solar cycle variations, and compare expected price fluctuations with price variations recorded in medieval England.
Usually the articles on astro-ph relate more to the state of astronomy today, rather than historical applications of astronomical data. Astronomer William Herchel noted that a relationship between wheat prices and sunspots in 1801. This work is a more detailed account of that relationship.
The authors found that during the 17th century, minimums in solar activity directly correlated with higher wheat prices. A BBC article talks about some of the theories sparked by this relationship.
The effects of the solar activity on Earth’s weather is not clearly understood yet, and is still being studied . A recent study has shown that, at least in the United States, periods of increased solar activity are usually accompanied by periods of greater cloud cover. In addition, storm tracks are pulled north by about 400 miles during solar peak activity.